This invention relates to a drive arrangement for a dental handpiece in order to drive a dental tool at different speeds.
More particularly, the invention is concerned with a straight or angular dentists' handpiece having an elongated handpiece sleeve having a drive motor arranged therein. The shaft of the drive motor drives or is connected with the input shaft of a planetary gear in order to drive a tooth treatment tool which can be inserted in the tip of the handpiece. Since it is necessary for the dentist to drive the tool at different speeds, it is necessary to provide for speed adjustments or variations. For this purpose, a transmission member is provided to transmit different speeds to the dental tool. The transmission member can be brought into engagement with the planetary gear in different transmission ratios. In order to establish different transmission ratios, the transmission along an axis is displaceable parallel to the axis of the handpiece sleeve by means of an external shift member on the handpiece.